Dos boot Hard drive failure

I'm trying to boot an harddrive into dos 6.22, i format the harddrive after booting into dos 6.22 form a disk, i run format c:/s. after that if i reboot on the disk, a can acces the harddrive, and see the command.com, but i can't boot on the harddrive, i always receive the message "hard drive failure"What's wrong?